Storage of high boiling distillate fractions



3 to it sodium nitn'te in an amount of 0.2%. A third 55,000 bbl. tank of gas oil had N:Ndisalicylidenel:2 diamino-propane added in an amount of lbs. per 1000 bbls. of gas oil and like the other tanks was also stored over a body of water. This body of water had sodium chromate added to it in an amount of 0.2%. These tanks were left on storage for one month and then sampled. In the following table comparative tests are given for the total sediment content of the gas oil in the several tanks after one months storage.

TABLE Il Plant storage in 55,000 barrel tanks Oil Inhibitor (l) Amt., Lbs/1,000 Bb 10. 0 Water Inhibitor (3) v Amt., Percent None None 0 2 0.2 Tests: Total Sediment, After 1 Month Storage, mgs./100 ml 0. 20 0 20 0. 08 0.04

1 N:Ndisalicylidene1:2-diamino propane. 2 Sodium Nitrite. 3 Sodium Chromate.

It will be seen from the foregoing results that the NzNedisalicylidene-l:Z-diamino propane alone did not reduce the total sediment but the N:Ndisalicylidene-l :2- diamino propane and sodium nitrite and the N:N'disali cylidene-i :Z-diamino propane and sodium chromate both reduced the total sediment substantially after one months storage. From these results it may be concluded that the N:N'disalicylidenel:2-diamino propane and the corrosion inhibitor effect an improved result over the N:Ndisalicylidenel:Z-diamino propane alone.

The sediment test is determined by filtering the oil and weighing the sediment recovered from the oil.

In order to show the etect of a corrosion inhibitor and an oxidation inhibitor on sediment formation and corrosion, samples of a gas oil were stored in the laboratory at 125 F. over a body of Water with an iron strip main- It will be noted also that the corrosion as determined as loss of Weight of the metal strip immersed in the oilwater interface had been reduced to an immeasurable quantity.

ln this particular test the sediment test was determined in the same manner as set out before.

Additional tests were made where a heating oil was stored in a laboratory at 125 F. over a body of water. Various portions of the heating oil which had a total sediment of 5.0 milligrams per 100 milliliters and had a metal loss of 5.37 milligrams of metal per milliliters of oil was divided into 6 portions. To two of the portions was added 2-4-6-tri-t-butylphenol in the amount of 10 lb./ 1000 bbls. The iirst of these portions was stored over a body of water to which no corrosion inhibitor was added. The second of these portions was stored over a body of water to which 0.20% by weight of sodium nitrite was added. A third and fourth portion had added to it 2-5-butyl-4-methoxyphenol in the amount of 10 lb./ 1000 bbls. The first portions having 2-5-butyl-4- methoxyphenol added to it was stored over a body of water which contained no corrosion inhibitor while the second of the portions to which 2-t-butyl-4-methoxypheuol was added was stored over a body of water which contained 0.20% by Weight sodium nitrite.

A fth and sixth portion had added to it 2,2bis(2 hydroxy 3 5 butyl t methoxyphenyl)propane in the amount of l0 lb./ 1000 bbls. The fifth portion was then stored over a body of Water to which no corrosion inhibitor had been added while the sixth portion was stored over a body of water which contained sodium nitrite in an amount of 0.20 weight per cent. In each case the various portions were stored in contact with a ferrous metal strip which was arranged to project into the oil and into the water. In other words, it passed through the oil-Water interface. These several portions were then placed on storage and samples withdrawn after 10 weeks storage and tested for total sediment and metal loss expressed as milligrams of metal per 100 milliliters of oil. These results are shown in Table IV.

tained in the oil-water interface. One portion of oil was stored over Water and had no inhibitor added either to the water or to the oil. A second portion had N:N disalicylidene-l:2-diamino propane added to the oil but nothing added to the water. A third portion had NzN- disalicylidene-l:2diamino propane added to the oil and sodium nitrite added to the Water while the fourth portion had N:Ndisalicylidenel:Z-diamino propane added to the oil and sodium chromate added to the water. These results are shown in Table III.

TABLE III Oil Inhibitor (l) (1) (1) 0 None 10.0 10.0 10.0

(3) Amt.,WPercent None None 0.2 0.2 Tests: p

Total Sediment, Inga/100 ml 0.01 0.10 0.03 0. 20 After 4 weeks storage 3. 10 0. 02 0.08

Metal Loss, mgs. metal/100 m1. of oil,

after 4 weeks' storage 2.69 2.18 0. 00 0. 00

Similar runs we re made with other inhibitors such as a polyethanol rosin amine type, a nitro aromatic type, 4,4- isopropyl1dene-bis(2 isopropyDphenol, distilled petrov leum phenols, and an unidentified commercial inhibitor sold under the trade name Sustane" by the Universal Oil Products Company. In each case a marked reduction in the formation of sediment with total elimination of measurable corrosion was eiected.

From the foregoing data it will be seen that by the practice of the present invention it is possible to store middle distillates, such as gas oil and heating oil fractions, in metal tanks in contact with a body of water so that deterioration of the gas oil or heating oil does not occur. In short the presence of unstable materials in the gas oil or heating oil when practicing our invention will not result in formation of undesirable sediment which if left to form may clog burner tips or result in corrosion of metal surfaces with which the gas oil or heating oil comes in contact. Thus the presence of an oxidation inhibitor and a corrosion inhibitor is necessary simultaneously to obtain the beneficial results of our invention. Furthermore, it may be seen that the gas oil or heating oil or other middle distillate may be stored at atmospheric temperatures, such as temperatures ranging from about 40 up to about 100 F. or may be stored at even higher temperatures, such as F. or higher. This latter is important especially when considering the fact that the aircarft industry is relying to a great extent on iet engines as a means for propulsion. Thus it is entirely possible that middle distillates boiling in the range from 300 to 900 F. may be stored at high temperatures for exceedingly long times. By adding an oxidation inhibitor to the oil and a corrosion inhibitor to the water over which the oil is ordinarily stored it is possible to alleviate the sediment problem and to eliminate the corrosion problem.

By way of explanation, the water which is found in the storage tanks in which gas oil and heating oil are stored results from atmosphereic moisture condensation and from processing operations by which the oil becomes substantially saturated with water which drops out on storage.

The nature and objects of the present invention having been completely described and illustrated, what we wish to claim as new and useful and to secure by Letters Patent is:

1. In the storage of a distillate fraction boiling in the range from about 300 to about 900 F. having a tendency to form sediment and corrode ferrous metals in the presence of water on storage in which said fraction is maintained in contact with a ferrous metal surface and a body of water, the step of maintaining simultaneously in said distillate a phenolic oxidation inhibitor in an amount in the range from 1 to 15 pounds per 1000 barrels of said disillate and in said body of water a water soluble corrosion inhibitor selected from the group consisting of the alkali metal nitrites and the alkali metal chromates in an amount in the range between 100 and 5000 p. p. m., whereby sediment formation in said distillatde and corrosion of said surface is substantially eliminate 2. A method in accordance with claim 1 in which the oxidation inhibitor is a petroleum phenol.

3. A method in accordance with claim 1 in which the corrosion inhibitor is an alkali metal nitrite.

4. A method in accordance with claim 1 in which the corrosion inhibitor is alkali metal chromate.

5. A method in accordance with claim 1 in which the oxidation inhibitor is 2-4-6-tri-t-butyl phenol.

6. A method in accordance with claim l in which the oxidation inhibitor is 2-t-butyl-4-methoxy phenol.

7. A method in accordance with claim 1 in which the oxidation inhibitor is 2,2-bis(2-hydroxy-3-5-butyl-t-methoxyphenyl) propane.

8. A method in accordance with claim 1 in which the oidatlion inhibitor is 4,4-isopropylidene-bis(2-isopropyl) p eno 9. A method in accordance with claim 1 in which the oxidation inhibitor is N:N'disalicylidene1:2-diamino propane.

10. In the storage of a gas oil fraction having a tendency to form sediment and to corrode ferrous metals in the presence of water on storage in contact therewith in which the gas oil is maintained in contact with a ferrous metal surface and a body of water, the step of maintaining simultaneously in said gas oil a phenolic oxidation inhibitor in an amount in the range from 1 to 15 pounds per 1000 barrels of gas oil and in said body of water a water soluble corrosion inhibitor selected from the group consisting of the alkali metal nitrites and the alkali metal chromates in an amount in the range between 100 and 5000 p. p. m. whereby sediment formation in said fractiondand corrosion of said surface is substantially eliminate 11. A method in accordance with claim 10 in which the oxidation inhibitor is a phenol represented by the formula: HOA-CH=N-R-N=CHA-OH in which A is an aromatic ring and R is an aliphatic radical.

12. A method in accordance with claim 10 in which the oxidation inhibitor is N:Ndisalicylidene1:2-diaminopropane.

13. A method in accordance with claim 10 in which the corrosion inhibitor is sodium nitrite.

14. In the storage of a petroleum fraction boiling in the range from about 300 to about 900 F. having a tendency to form sediment and corrode ferrous metals in the presence of water on storage in contact therewith in which said fraction is maintained in contact with a ferrous metal surface and a body of water, the step of adding to the petroleum fraction a phenolic oxidation inhibitor in an amount in the range from 1 to 15 pounds per 1000 barrels of said fraction and to the body of water a water soluble corrosion inhibitor selected from the group consisting of sodium nitrite and sodium chromate in an amount in the range between and 5000 p. p. m. whereby sediment formation in said fraction and corrosion of said surface is substantially eliminated.

15. A method in accordance with claim 14 in which the oxidation inhibitor is N:Ndisalicylidene1:Z-diaminopropane.

16. A method in accordance with claim 14 in which the corrosion inhibitor is sodium nitrite.

17. A method in accordance with claim 14 in which the oxidation inhibitor is 2-4-6-tri-t-butyl phenol.

18. A method in accordance with claim 14 in which the oxidation inhibitor is 2tbuty14methoxy phenol.

19. A method in accordance with claim 14 in which the oxidation inhibitor is 2,2-bis(2-hydroxy-3-5-butyl-tmethoxyphenyl) propane.

20. A method in accordance with claim 14 in which the oxidation inhibitor is 4,4-isopropylidene-bis(2-isopropyl) phenol.

21. In a storage of a gas oil fraction boiling in the range from about 300 to about 900 F. having a tendency to form sediment and corrode ferrous metals in the presence of water on storage in contact therewith in which said fraction is maintained in contact with a ferrous metal surface and a body of water, the step of adding to the gas oil fraction 10 pounds of N:Ndisalicylidene 1:2-diamino-propane per 1000 barrels and to the body of water 500 p. p. m. of a water soluble corrosion inhibitor selected from the group consisting of sodium chromate and sodium nitrite, whereby sediment formation in said fraction and corrosion of said surface is substantially eliminated. I

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,050,732 Roberts Aug. 11, 1936 2,064,325 Sutton et al Dec. 15, 1936 2,181,121 Downing et al. Nov. 28, 1939 2,241,638 Field May 13, 1941 2,453,850 Mikeska et al Nov. 16, 1948 2,533,301 Watkins Dec. 12, 1950 2,533,304 Watkins Dec. 12, 1950 

1. IN THE STORAGE OF A DISSTILLATE FRACTION BOILING IN THE RANGE FROM ABOUT 300* TO ABOUT 900* F. HAVING A TENDENCY TO FORM SEDIMENT AND CORRODE FERROUS METALS IN THE PRESENCE OF WATER ON STORAGE IN WHICH SAID FRACTION IS MAINTAINED IN CONTACT WITH A FERROUS METAL SURFACE AND A BODY OF WATER, THE STEP OF MAINTAINING SIMULTANEOUSLY IN SAID DISTILLATE A PHENOLIC OXIDATION INHIBITOR IN AN AMOUNT IN THE RANGE FROM 1 TO 15 POUNDS PER 1000 BARRELS OF SAID DISTILLATE AND IN SAID BODY OF WATER A WATER SOLUBLE CORROSION INHIBITOR SELECTED FROM THE GROUP CONSISTING OF THE ALKALI METAL NITRITES AND THE ALKALI METAL CHROMATES IN AN AMOUNT IN THE RANGE BETWEEN 100 AND 5000 P. P. M., WHEREBY SEDIMENT FORMATION IN SAID DISTILLATE AND CORROSION OF SAID SURFACES IS SUBSTANTIALLY ELIMINATED. 